Single and Double Slit Diffraction

• What are the conditions for constructive interference of two waves?

  Path difference is nλ
• What are the conditions for destructive interference of two waves?

  Path difference is (n+½)λ
• What does the term monochromatic light mean?

  Single frequency or single wavelength light
• How are bright fringes formed in interference patterns?

  Peaks meet peaks or troughs meet troughs
• What does the diffraction intensity graph look like for a single slit with monochromatic light?

  Central maximum with symmetrical subsidiary maxima
• What happens to the pattern when white light passes through a green filter after a single slit?

  Pattern shows green light with reduced colors
• How does constructive interference occur?

  Waves have zero phase difference and reinforce
• How does destructive interference occur?

  Waves have a phase difference of π rad
• What is the effect of a single slit in the Young's double slit experiment?

  It makes light from the two slits coherent
• What is the appearance of the diffraction intensity graph for blue light compared to red light?

  Central maximum would be narrower for blue
• How does the intensity pattern change with higher frequency sound waves?

  Pattern becomes narrower with higher frequency
• What is observed on a screen with white light in a double slit experiment?

  Central white fringe with colored spectra
• How does replacing a violet laser with a green laser affect the pattern?

  Fringes become further apart with green
• What happens to the central maximum when red light is used instead of blue light?

  Central maximum becomes wider and dimmer
• How does the use of a diffraction grating affect the appearance of maxima?

  Greater order maxima spread out more
• Why does the intensity of a double-slit diffraction pattern reduce moving outwards from the center?

  Waves travel different distances causing phase differences
• What are the applications of diffraction gratings with a spectrometer?

  • Spectral analysis of light from stars
  • Chemical analysis
  • Measuring red shift and star rotation
• What is the wavelength range for red light transmitted by the filter?

  600 - 700 nm
• How does the central maximum width change with different light colors?

  Wider for red light than for blue light
• How does the energy distribution change when using red light instead of blue light?

  Energy is spread over a larger area
• What is the effect of increasing the screen distance in the double slit experiment?

  Increases fringe spacing and reduces uncertainty
• How does the appearance of the interference pattern change with a non-laser white light?

  Pattern shows a spectrum of colors
• What is the significance of the path lengths being constant in the Young's double slit experiment?

  Ensures coherent light from both slits